Like many processes in the library material resource-sharing supply chain, the effectiveness of centralized manual sorting is measured by the rate at which items can be sorted. The rate of items sorted depends on the amount of handling required to sort the item to its library destination accurately and the amount of distance a sorter needs to walk to move between sort locations. Fewer han- dl ings and shorter walking distances lead to a higher sort rate. Determining and monitoring this rate allows the delivery manager to evaluate the efficiency of the centralized sorting process.
How materials are separated when shipped to and from libraries greatly affects the speed with which they can be sorted manually at a central site. To provide an example of how to determine sorting rates and how to improve these rates, we use the following parameters: materials are shipped in plastic totes that hold an average of thirty-five items each, there are twenty libraries served by the delivery ser vice that send on average one hundred totes of materials to the central sorting location each day, and libraries do not perform any preseparation of the materials.
To determine how quickly sorting staff are able to process materials in this setup, divide the number of totes sorted in a single hour by the number of staff who sorted during that full hour. To get the most accurate rate, perform this sample study a few times over a few different days. In this example, we stipulate that the average number of totes sorted by a single person in a one-hour period averages ten totes, or 350 items. Thus, to sort through the hundred totes of mate- rials received on average each day at the central sort location, ten hours of labor time are required.
Keeping a regular record of how many totes are picked up at each delivery location each day allows you to find out if the sorting rate can be improved. In this example, the library system delivers to twenty libraries. Five of those libraries are part of the city’s branch delivery system. This city has the largest population in the library system, and the delivery data indicate that fifty of the totes shipped by delivery each day go to these five library locations.
As noted above, distance and handling directly relate to labor time with sort- ing. In this centralized sorting setup, the materials are sorted directly into the totes. The totes are arranged on shelves in a square with five library sort locations on each row of the four shelving sections in the square. With the data indicating that half of the materials sorted go to the five locations of the city library, it may make sense to ask participating libraries to place materials destined for one of the five city locations in one tote and items for the other fifteen locations in the other tote. A simple separation like this should not add significant time on the library
end of preparing materials for delivery, since the library already sends more than one tote each day in delivery and this level of separation will be easy for library staff to perform.
With this separation, the central sort site can be configured to have the five largest locations on one row of shelves and the other fifteen libraries set up for sorting on the other three rows of shelving. With this new layout and sorting design, a new time study can be done to determine the sorting rate for materials to the five largest library sort locations and the rate for sorting to the remaining fifteen library sort locations. A sorting rate increase would be the result of reduc- ing the distance sorting staff walk when sorting items between the various library sort locations.
Suppose that in our example the rate for the five largest libraries shelving row increased to eighteen totes sorted per labor hour and in the other three rows with the remaining fifteen library sort locations the rate increased to fourteen totes per hour. To get the total number of sorting hours it should now on average take to process the day’s workload of one hundred totes, we have 50 ÷ 18, for a total of about 2.75 hours, and 50 ÷ 14, for a total of about 3.5 hours. Thus the total time to sort through the daily volume has been reduced from 10 to 6.25 hours.
This amounts to more than nine hundred hours of labor saved over the course of one year, all made possible with a simple change in the process with a negligible impact on the libraries doing the material separation.
Another way to look at making a separation feasible in terms of impact on the library of is to study the totes being sent to libraries alphabetically. You may find that half of the volume sorted at the central sort site goes to libraries that alphabetically fall between A and M and the other half is shipped to libraries fall- ing between N and Z. This would be another easy separation for libraries to do with little impact on library staffing time. The same concept can be applied to library systems using a numerical labeling code system.
The previous example illustrates how libraries can assist sorting efficiency at a centralized sorting location. Now consider how a central sort site can sepa- rate materials being delivered to libraries to improve their handling efficiency at delivery.
Libraries, especially larger libraries, often process incoming delivery materi- als in different locations in the library according to where particular items need to end up. The most basic separation, and typically most feasible at a central sort site, is that between materials filling hold requests and materials being returned to the library for reshelving. In many libraries, hold materials for patron pickup are checked in at the circulation desk. Materials being returned to an owning
library to be shelved are often handled in a back workroom, where they can be checked in and then presorted onto book trucks for shelving.
If all these materials are delivered to a library mixed together in totes, library staff have to go through the extra handling step of separating items for either the circulation desk or the back room book trucks for shelving. This separation could instead be done at the centralized sorting location. The sorting area layout could be designed to have two totes tiered on the shelving, with one tote for “return” materi- als and the other for “hold” materials. Just as the separation done by libraries is sim- plified so as to not affect library staff time, this level of separation of materials going to libraries should not have a negative impact on the central sort site’s sorting rates.
Such a separation is usually feasible only in a single-hub closed-loop library system. There, it is possible to distinguish between “return” and “hold” simply by giving materials for holds a special label. Items being returned to an own- ing library could be sorted by ownership tags permanently placed on the items.
Sorting staff could be trained to sort materials without labels into the “return”
tote and items with labels into the “hold” tote.
In a delivery network where materials are transferred between multiple sort- ing/delivery hubs, labels are typically required on all items in order to facilitate quick and accurate sorting. Expecting sorting staff at each sorting hub to mem- orize which libraries are served by which hub in the delivery network is not realistic. This is especially the case when a private courier ser vice is handling the sorting and the delivery, since this courier is likely not as familiar with the deliv- ery network as a library-run delivery ser vice.
automated Materials Handling
Automated materials handling (AMH) has been in widespread use throughout many industries and businesses in the private sector for many years. In the past ten years, AMH systems have increasingly made their way into the library, partic- ularly in Europe. The majority of these systems have been employed in automat- ing the handling of materials being returned to libraries. A well-designed system can greatly reduce the amount of labor time associated with checking in returned materials and getting the materials back to their shelf locations.
In the past handful of years, AMH systems have been designed for imple- mentation at centralized sorting facilities. More and more companies specializing in AMH have directed their ser vices to this market. The systems currently on the market for centralized library delivery sorting vary greatly in design and potential for return on investment. Determining whether an AMH system is right for your
delivery ser vice sorting involves research and several decisions. The purchase cost of these systems, even the smallest, can be quite high. A basic sorting belt system without supplementary container handling conveyance equipment or transport bins can cost at a minimum $500,000. Larger systems with advanced container handling equipment or transport bins can cost $2 million or more. Though an AMH system works for sorting operations of all sizes, budget realities make AMH implementation a possibility only at larger library systems handling a high vol- ume of materials.
Basic AMH functions are really quite simple and generally fall into one of two categories: conveyance of containers and automated sorting. Sorting sites considering AMH are usually most interested in the sorting functions.
In the first category, robotic crane or cart systems have been designed to con- vey totes at the central sort site. Some of these systems move incoming totes to the sorting system location in the facility to eliminate any manual lifting of the totes.
This same system then takes totes that have been filled in the sorting process away from the sorting system location, orga nizes them according to routes, and deliv- ers them to a loading dock area ready for truck loading and delivery. FKI Logistex designed and installed such a system at the King County (Washington) Library System. This system was designed to work with the plastic totes the libraries were already using for delivery.
In another type of a material transport system, materials are sorted into carts or wheeled bins that also serve as the containers used to take the materials to and from libraries. Seattle Public Library’s main library uses such a system, designed and installed by Tech Logic. Materials in the sorting system are placed into what Tech Logic calls Smart Bins, which, after they have been filled, are then simply rolled onto trucks with liftgates for delivery to libraries. Both systems, and those available from other vendors, are designed to ease the physical transfer of materi- als within a central sort site and on delivery routes.
The sorting system itself, which redistributes incoming materials at the cen- tral sort site to their respective library destinations, is typically a belt-driven sys- tem with the ability to read bar codes or radio-frequency identification (RFID) tags, communicate with the ILS shared catalog automation software, and place items in a particular library’s tote or bin ready for transport. The first part of this system is the induction point, where materials to be sorted are placed into the system, typically onto a conveyor belt. This can be done either manually or by specialized induction equipment.
Once an item is on the conveyor belt, its bar code or RFID tag is scanned by a reader. The reader then connects to the automated catalog to determine where
to ship the item. After this information is received by the sorting system, the item travels along the conveyor belt until it reaches the designated library’s chute. The belt system is often set up with what is called a cross-belt, which grabs the item and sends it through a chute into a tote or bin for the library. The system can be programmed to have items sorted a number of ways. Many sorting systems are programmed to have two chute locations for each library, so that hold items go into one chute and returns into the other.
There are many factors to consider in designing an AMH system for central- ized library delivery sorting:
whether the system will handle bar codes, RFID, or both
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how materials are inducted into the sort system
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what kind of container materials are placed into as they are sorted
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the facility space footprint required to house the system
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the communication between the system and the ILS automation
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throughput—the number of items the system can sort per hour
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system maintenance
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labor time and costs required to operate and manage the system
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The design, functionalities, and costs of AMH systems vary greatly. The best way to investigate the suitability of an AMH system for your centralized sorting operation is to contact vendors, who can provide customer references and work with you to design a system specific to your needs and budget.
Bar Code and RFID
The complexity and potential of an AMH system have much to do with whether library materials are tagged with bar codes or RFID. If the library materials already have RFID tags, then choosing an AMH system with an RFID reader is an easy decision. Having a system that functions with RFID saves material induction point labor time, simplifies the physical functionality requirements of the system, and increases the throughput rate of the AMH system. An AMH system that must manage materials with bar codes can slow down the throughput rate, increase the labor time necessary to induce items onto the sorting belt, and increase the required complexity of the system’s physical design. It might, then, seem that purchasing an AMH system that functions with RFID would be the prudent deci- sion. However, since most libraries currently have bar codes on their materials, tagging library materials with RFID is an additional major cost consideration.
The operational functionality of bar codes requires that they be visible and correctly orientated for the bar code reader to scan the item. This requires that
items be inducted, or place, into the AMH sorting system in a manner that makes this possible. This can involve manually placing an item with the bar code facing up on a sorting belt or designing the functionality into the AMH for the item to be manipulated by the system to rotate the item until the bar code can be accu- rately scanned.
Placing items manually into the sorting system has a long-term negative cost impact. The labor time in performing this function is an ongoing cost that grows over time as wages and volume increase. The system must be designed with the capability for having manual induction points along the sorting belt added in the future to increase the number of operators who can feed materials into the system in order to process the delivery material volume in a similar time frame.
Without additional induction points, the workday has to be extended to handle any increase in volume. The number of potential induction points is limited by the system’s throughput capabilities. This is true for manual or automated induction.
Designing the AMH to orient bar codes for scanning does slow down the throughput, but it allows the system to include automated induction, which in the long run eliminates the labor costs incurred with manual induction.
Advantages, Disadvantages, and Costs of AMH
The decision to convert a centralized sorting operation to AMH usually comes down to cost. As delivery volume continues to grow, managers of sorting opera- tions are constantly trying to find ways to improve productivity and reduce costs.
There are often ways that libraries and central sort sites can work together to increase efficiency, but even with exceptional cooperation there is a limit to how fast materials can be handled manually while maintaining accuracy and safety.
Realistically, in a manual sorting setup the ceiling of productivity lies in the range of 500–700 items per labor hour. Also, because we are human we make errors, and the faster we try to go the more errors we make. With all this in mind, how do we determine when it makes sense to consider automating the sorting part of the resource-sharing supply chain?
Let’s first determine the potential return on investment (ROI) of converting to AMH. Each situation is different, and acting as if you have determined a cost certainty is a large operational leap. Suppose you determine that you can staff an AMH system with two operators. If you are wrong and end up needing three operators, your ongoing labor costs increase by 50 percent, which will greatly affect your return. Still, with such potential uncertainty there are some assump- tions and calculations that can provide accurate estimates.
For this purpose we use the following data: the current sorting operation processes 20,000 items on average each day, and staff is individually able to sort 500 items per hour. With these assumptions, 40 hours of staff time are needed each day to process incoming materials. This rate serves as the basis for determin- ing any labor ROI with a move to AMH.
To determine an equivalent rate with AMH, two pieces of information are needed—system throughput and staff time. Assume that the system can sort 2,000 items per hour, which in this situation means that it must operate 10 hours per day to process the 20,000 items currently handled. If only two people are needed to operate the system during these 10 hours, then this operation potentially cuts its sorting labor costs on an ongoing basis by 50 percent. If this operation is run five days per week, 100 hours of labor are saved each week. Over the course of the year, say the hourly wage with taxes is $12.50, or $65,000 saved per year in labor. If the purchase price of the AMH system is $600,000, that amounts to a little more than nine years for the investment to pay for itself.
There are, however, other cost implications. But before we detail them, let us emphasize this important point. An ROI calculation is done with the manager’s best estimates and information from the vendor, but there is potential for over- estimating. How do you know if what you think is needed to operate the system is correct, and how do you know if you are getting the most realistic numbers from the vendor? The most important part of the process of researching an AMH system is talking with people from library systems using the AMH system you are investigating. You may hear that this particular AMH system’s throughput is actually closer to 1,500 items per hour, or that they found three and sometimes four operators are needed to manage the system. Purchasing and converting to an AMH system is definitely a buyer-beware situation.
So, what are other factors to consider when calculating ROI? First, ongoing maintenance and ser vice are cost items. Most vendors offer yearly tiered ser vice plans to help fit your particular system and budget capabilities. On the savings side, there is a potential for a big advantage by moving to an AMH system, though it is hard to calculate: the potential savings possible at the library end of the sup- ply chain. A great advantage of AMH is that for the most part library materials do not need to be labeled. In our example, if the central sort site is handling 20,000 items each day, that means the libraries are cumulatively receiving 20,000 items each day and preparing another 20,000 items for the next day’s delivery. If half of those items need labeling to indicate they are holds going to another library, there are 20,000 items either being labeled or having labels removed each day.
If it takes only fives seconds to handle the labeling at the libraries, that could